Display device and display system

ABSTRACT

A display device includes a liquid crystal display panel having a display region, pixels provided in the display region and arranged in a matrix (row-column configuration) in a first direction and a second direction different from the first direction, and a pixel gradation corrector correcting a gradation value of a first pixel in accordance with gradation values of second pixels adjacent to the first pixel, the pixel gradation corrector multiplying a value indicating sensitivity with which the first pixel is influenced by the second pixels and a value indicating strength of influence that the second pixels exert on the first pixel together, and subtracting the multiplied value from an input gradation value of the first pixel to calculate an output gradation value to the first pixel.

CROSS-REFERENCE TO RELATED APPLICATION

This application claims the benefit of priority from Japanese PatentApplication No. 2020-152416 filed on Sep. 10, 2020, the entire contentsof which are incorporated herein by reference.

BACKGROUND 1. Technical Field

The present invention relates to a display device and a display system.

2. Description of the Related Art

A virtual reality (VR) system changes image display along with movementof a point of view to cause a user to feel a sense of virtual reality.As a display device to achieve such a VR system, disclosed is atechnique mounting a head mounted display (hereinafter also referred toas an “HMD”) on the head and displaying images corresponding to themotion of the body or the like, for example (WO 2018/211672, forexample).

In the HMD used in the VR system, a displayed image is enlarged by aneyepiece, and thus a display panel is required to have higherdefinition. The displayed image is enlarged, whereby gaps between pixelsare likely to look like a grid. Thus, a liquid crystal display panelhaving a high pixel opening ratio is used as the display panel of theHMD, thereby producing the advantage that image display with a lesssense of grid is enabled. In lateral electric field mode liquid crystaldisplay panels such as in-plane switching (IPS) including fringe fieldswitching (FFS), along with higher definition, there is a possibilitythat mutual electric lines of force exert influence on each otherbetween adjacent pixels to cause color shift and a reduction in theaccuracy of displayed colors.

What is disclosed herein has been made in view of the above problem, andan object thereof is to provide a display device and a display systemthat can inhibit a reduction in the accuracy of displayed colors alongwith higher definition.

SUMMARY

A display device according to an embodiment of the present disclosureincludes a liquid crystal display panel having a display region, pixelsprovided in the display region and arranged in a matrix (row-columnconfiguration) in a first direction and a second direction differentfrom the first direction, and a pixel gradation corrector correcting agradation value of a first pixel in accordance with gradation values ofsecond pixels adjacent to the first pixel, the pixel gradation correctormultiplying a value indicating sensitivity with which the first pixel isinfluenced by the second pixels and a value indicating strength ofinfluence that the second pixels exert on the first pixel together, andsubtracting the multiplied value from an input gradation value of thefirst pixel to calculate an output gradation value to the first pixel.

A display system according to an embodiment of the present disclosureincludes a display device including a liquid crystal display panelhaving a display region, and pixels provided in the display region andarranged in a matrix (row-column configuration) in a first direction anda second direction different from the first direction, and an imagegeneration device including a pixel gradation corrector correcting agradation value of a first pixel in accordance with gradation values ofsecond pixels adjacent to the first pixel, the pixel gradation correctormultiplying a value indicating sensitivity with which the first pixel isinfluenced by the second pixels and a value indicating strength ofinfluence that the second pixels exert on the first pixel together, andsubtracting the multiplied value from an input gradation value of thefirst pixel to calculate an output gradation value to the first pixel.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a configuration diagram of an example of a display systemaccording to a first embodiment;

FIG. 2 is a schematic diagram of an example of a relation between adisplay panel and an eye of a user;

FIG. 3 is a block diagram of an example of components of an imagegeneration device and a display device of the display system illustratedin FIG. 1;

FIG. 4 is a circuit diagram of a display region according to the firstembodiment;

FIG. 5 is a schematic diagram of an example of the display panelaccording to the first embodiment;

FIG. 6 is a sectional view schematically illustrating a section of thedisplay panel according to the first embodiment;

FIG. 7 is a diagram of a first example of a pixel arrangement accordingto the first embodiment;

FIG. 8 is a schematic sectional view of the display panel forillustrating influence by mutual electric lines of force between pixelsadjacent to each other;

FIG. 9 is a diagram of display relative intensity in the case of whitedisplay and monochromatic display of a pixel of each color;

FIG. 10 is a diagram of a second example of the pixel arrangementaccording to the first embodiment;

FIG. 11 is a diagram of a third example of the pixel arrangementaccording to the first embodiment;

FIG. 12 is a block diagram of a pixel gradation correction circuitaccording to the first embodiment;

FIG. 13 is a diagram of an example of a function indicating sensitivitywith which a pixel for which the pixel gradation will be corrected isinfluenced by adjacent pixels;

FIG. 14A is a diagram of an example of the shape of pixel electrodes inthe first example of the pixel arrangement illustrated in FIG. 7;

FIG. 14B is a diagram of an example in which the shape of the pixelelectrodes is different between an even row and an odd row in the firstexample of the pixel arrangement illustrated in FIG. 7; and

FIG. 15 is a block diagram of a pixel gradation correction circuitaccording to a second embodiment.

DETAILED DESCRIPTION

The following describes aspects (embodiments) to perform the presentdisclosure in detail with reference to the accompanying drawings. Thedetails described in the following embodiments do not limit the presentdisclosure. The components described in the following include ones thatcan easily be thought of by those skilled in the art and substantiallythe same ones. Further, the components described in the following can becombined with each other as appropriate. What is disclosed herein isonly by way of example, and some appropriate modifications with the gistof the disclosure maintained that can easily be thought of by thoseskilled in the art are naturally included in the scope of the presentdisclosure. The drawings may be represented more schematically for thewidth, thickness, shape, and the like of parts than those of actualaspects in order to make the description clearer; they are only by wayof example and do not limit the interpretation of the presentdisclosure. In the present specification and drawings, componentssimilar to those previously described for the drawings previouslydescribed are denoted by the same symbols, and a detailed descriptionmay be omitted as appropriate.

First Embodiment

FIG. 1 is a configuration diagram of an example of a display systemaccording to a first embodiment. FIG. 2 is a schematic diagram of anexample of a relation between a display panel and an eye of a user.

In the present embodiment, this display system 1 is a display systemchanging display in accordance with the motion of the user. The displaysystem 1 is a virtual reality (VR) system stereoscopically displaying aVR image indicating a three-dimensional object or the like on a virtualspace and changing the stereoscopic display along with the direction(position) of the head of the user to cause the user to feel a sense ofvirtual reality, for example.

As illustrated in FIG. 1, the display system 1 has a display device 100and an image generation device 200, for example. The display device 100and the image generation device 200 are connected to each other in awired manner via a cable 300, for example. The cable 300 includes aUniversal Serial Bus (USB) or High-Definition Multimedia Interface (HDMI(registered trademark)) cable, for example. The display device 100 andthe image generation device 200 may be connected to each other viawireless communications.

In the present disclosure, the display device 100 is used as a headmounted type display device fixed to a mounting member 400 and mountedon the head of the user, for example. The display device 100 includes adisplay panel 110 for displaying an image generated by the imagegeneration device 200. In the following, the aspect in which the displaydevice 100 is fixed to the mounting member 400 is also referred to as a“head mounted display (HMD)”.

In the present disclosure, examples of the image generation device 200include personal computers and electronic apparatuses such as gamemachines. The image generation device 200 generates a VR imagecorresponding to the position or the attitude of the head of the userand outputs the VR image to the display device 100. The image generatedby the image generation device 200 is not limited to the VR image.

The display device 100 is fixed at a position where when the user wearsthe HMD, the display panel 110 is placed before both eyes of the user.The display device 100 may include a voice output device such as aspeaker at positions corresponding to both ears of the user when theuser wears the HMD apart from the display panel 110. As described below,the display device 100 may include a sensor detecting the position, theattitude, or the like of the head of the user wearing the display device100, or a gyro sensor, an acceleration sensor, or an azimuth sensor, forexample. The display device 100 may contain the functions of the imagegeneration device 200.

As illustrated in FIG. 2, the mounting member 400 has a lens 410corresponding to both eyes E of the user, for example. The lens 410,when the user wears the HMD, magnifies an image displayed on the displaypanel 110 and forms the image on the eye E of the user. The uservisually recognizes the image displayed on the display panel 110 andmagnified by the lens 410. Although FIG. 2 illustrates an example inwhich one lens is placed between the eye E of the user and the displaypanel 110, a plurality of lenses corresponding to respective both eyesof the user may be included, for example. The display panel 110 may beplaced at a position different from before the eye of the user.

In the present embodiment, the display panel 110 assumes a lateralelectric field mode liquid crystal display panel such as in-planeswitching (IPS) including fringe field switching (FFS) including animage liquid crystal element.

In the display device 100 used in the VR system illustrated in FIG. 1,as illustrated in FIG. 2, the image displayed on the display panel 110is magnified and formed on the eye E of the user. Given this, a displaypanel with higher definition is demanded. The displayed image ismagnified, whereby gaps between pixels are likely to look like a grid.Given this, using a liquid crystal display panel having a high pixelopening ratio brings about the advantage that image display with a lesssense of grid is enabled.

FIG. 3 is a block diagram of an example of components of the imagegeneration device and the display device of the display systemillustrated in FIG. 1. As illustrated in FIG. 3, the display device 100includes two display panels 110, a sensor 120, an image separationcircuit 150, and an interface 160.

The display device 100 includes the two display panels 110. As to thetwo display panels 110, one is used as the display panel 110 for theleft eye, whereas the other is used as the display panel 110 for theright eye.

Each of the two display panels 110 has a display region 111 and adisplay control circuit 112. The display panel 110 has a light sourcedevice (not illustrated) illuminating the display region 111 frombehind.

In the display region 111, P₀×Q₀ (P₀ in a row direction (an X direction)and Q₀ in a column direction (a Y direction)) pixels Pix are arranged ina two-dimensional matrix (row-column configuration). In the presentembodiment, a pixel density of the display region 111 is 806 ppi, forexample. FIG. 3 schematically illustrates the arrangement of a pluralityof pixels Pix, and a detailed arrangement of the pixels Pix will bedescribed below.

The display panel 110 has scan lines extending in the X direction andsignal lines extending in the Y direction crossing the X direction. Inthe display panel 110, the pixels Pix are each placed in an areasurrounded by signal lines SL and scan lines GL. The pixels Pix eachhave a switching element (thin film transistor (TFT)) connected to asignal line SL and a scan line GL and a pixel electrode connected to theswitching element. A plurality of pixels Pix arranged along an extensiondirection of the scan line GL are connected to one scan line GL. Aplurality of pixels Pix arranged along an extension direction of thesignal line SL are connected to one signal line SL.

Out of the two display panels 110, the display region 111 of one displaypanel 110 is for the right eye, whereas the display region 111 of theother display panel 110 is for the left eye. Although this exampleexemplifies a case in which the display panel 110 has the two displaypanels 110 for the left eye and for the right eye, the display device100 is not limited to the structure including two display panels 110.One display panel 110 may be employed, in which the display region ofthe one display panel 110 may be divided into two so that an image forthe right eye is displayed on a right half region, whereas an image forthe left eye is displayed on a left half region, for example.

The display control circuit 112 includes a driver integrated circuit(IC) 115, a signal line connection circuit 113, and a scan line drivecircuit 114. The signal line connection circuit 113 is electricallyconnected to the signal lines SL. The driver IC 115 controls on and offof switching elements (TFTs, for example) for controlling the operation(light transmittance) of the pixels Pix by the scan line drive circuit114. The scan line drive circuit 114 is electrically connected to thescan lines GL.

The sensor 120 detects information from which the orientation of thehead of the user can be estimated. The sensor 120 detects informationindicating the motion of the display device 100, whereas the displaysystem 1 estimates the orientation of the head of the user wearing thedisplay device 100 on the head based on the information indicating themotion of the display device 100, for example.

The sensor 120 detects information from which the orientation of theline of sight can be estimated using at least one of the angle, theacceleration, the angular velocity, the azimuth, and the distance of thedisplay device 100, for example. For the sensor 120, a gyro sensor, anacceleration sensor, or an azimuth sensor can be used, for example. Thesensor 120 may detect the angle and the angular velocity of the displaydevice 100 by the gyro sensor, for example. The sensor 120 may detectthe direction and the magnitude of acceleration acting on the displaydevice 100 by the acceleration sensor, for example.

The sensor 120 may detect the azimuth of the display device 100 by theazimuth sensor, for example. The sensor 120 may detect the movement ofthe display device 100 by a distance sensor or a Global PositioningSystem (GPS) receiver, for example. The sensor 120 may be another sensorsuch as a light sensor or may be a combination of a plurality of sensorsso long as it is a sensor for detecting the orientation of the head, achange in the line of sight, the movement, or the like of the user. Thesensor 120 is electrically connected to the image separation circuit 150via the interface 160 described below.

The image separation circuit 150 receives image data for the left eyeand image data for the right eye sent from the image generation device200 via the cable 300 and sends the image data for the left eye to thedisplay panel 110 displaying the image for the left eye and sends theimage data for the right eye to the display panel 110 displaying theimage for the right eye.

The interface 160 includes a connector to which the cable 300 (FIG. 1)is connected. A signal from the image generation device 200 is input tothe interface 160 via the connected cable 300. The image separationcircuit 150 outputs a signal input from the sensor 120 to the imagegeneration device 200 via the interface 160 and an interface 240. Thesignal input from the sensor 120 includes the information from which theorientation of the line of sight can be estimated described above.

Alternatively, the signal input from the sensor 120 may be output to acontrol circuit 230 of the image generation device 200 directly via theinterface 160. The interface 160 may be a wireless communication deviceand may transmit and receive information to and from the imagegeneration device 200 via wireless communication, for example.

The image generation device 200 includes an operator 210, a storage unit220, the control circuit 230, and the interface 240.

The operator 210 receives operations by the user. The operator 210 canbe an input device such as a keyboard, buttons, or a touch screen. Theoperator 210 is electrically connected to the control circuit 230. Theoperator 210 outputs information corresponding to the operations to thecontrol circuit 230.

The storage unit 220 stores therein a computer program and data. Thestorage unit 220 temporarily stores therein a processed result of thecontrol circuit 230. The storage unit 220 includes a storage medium. Thestorage medium includes a read only memory (ROM), a random access memory(RAM), a memory card, an optical disc, or a magnetooptical disc, forexample. The storage unit 220 may store therein the data of an image tobe displayed on the display device 100.

The storage unit 220 stores therein a control program 211 and a VRapplication 212, for example. The control program 211 can provide afunction on various kinds of control to operate the image generationdevice 200, for example. The VR application 212 can provide a functionto cause the display device 100 to display the VR image. The storageunit 220 can store therein various kinds of information input from thedisplay device 100 such as data indicating a detection result of thesensor 120, for example.

The control circuit 230 includes a micro control unit (MCU) or a centralprocessing unit (CPU), for example. The control circuit 230 cancomprehensively control the operation of the image generation device200. The various kinds of functions of the control circuit 230 areimplemented based on the control of the control circuit 230.

The control circuit 230 includes a graphics processing unit (GPU)generating an image to be displayed, for example. The GPU generates animage to be displayed on the display device 100. The control circuit 230outputs the image generated by the GPU to the display device 100 via theinterface 240. Although the present embodiment describes a case in whichthe control circuit 230 of the image generation device 200 includes theGPU, this is not limiting. The GPU may be provided in the display device100 or the image separation circuit 150 of the display device 100, forexample. In this case, the display device 100 may acquire data from theimage generation device 200, an external electronic apparatus, or thelike, and the GPU may generate an image based on the data, for example.

The interface 240 includes a connector to which the cable 300 (refer toFIG. 1) is connected. A signal from the display device 100 is input tothe interface 240 via the cable 300. The interface 240 outputs a signalinput from the control circuit 230 to the display device 100 via thecable 300. The interface 240 may be a wireless communication device andmay transmit and receive information to and from the display device 100via wireless communication, for example.

Upon execution of the VR application 212, the control circuit 230 causesthe display device 100 to display an image corresponding to the motionof the user (the display device 100). Upon detection of a change in theuser (the display device 100) with the image displayed on the displaydevice 100, the control circuit 230 changes the image displayed on thedisplay device 100 to an image of the changed direction. The controlcircuit 230 creates an image based on a standard point of view and astandard line of sight on a virtual space at the time of startingcreation of an image, when detecting the change in the user (the displaydevice 100), changes the point of view or the line of sight whencreating the displayed image from the standard point of view or thestandard line of sight direction in accordance with the motion of theuser (the display device 100), and causes the display device 100 todisplay an image based on the changed point of view or line of sight.

The control circuit 230 detects the movement of the head of the user toa right direction based on the detection result of the sensor 120, forexample. In this case, the control circuit 230 changes the image beingcurrently displayed to an image when the line of sight is changed to theright direction. The user can visually recognize an image in the rightdirection of the image being displayed on the display device 100.

Upon detection of the movement of the display device 100 based on thedetection result of the sensor 120, the control circuit 230 changes theimage in accordance with the detected movement, for example. Whendetecting that the display device 100 has moved toward the front, thecontrol circuit 230 changes the image being currently displayed to animage when the display device 100 has moved to the front of the imagebeing currently displayed. When detecting that the display device 100has moved to a rear direction, the control circuit 230 changes the imagebeing currently displayed to an image when the display device 100 hasmoved to the rear of the image being currently displayed. The user canvisually recognize an image in its own moving direction from the imagebeing displayed on the display device 100.

FIG. 4 is a circuit diagram of the display region according to the firstembodiment. In the following, the scan lines GL described abovecollectively refer to a plurality of scan lines G1, G2, and G3. Thesignal lines SL described above collectively refer to a plurality ofsignal lines S1, S2, and S3. Although in the example illustrated in FIG.4 the scan lines GL and the signal lines SL are orthogonal to eachother, this is not limiting. The scan lines GL and the signal lines SLare not necessarily orthogonal to each other, for example.

As illustrated in FIG. 4, in the present disclosure, the pixel Pixincludes a pixel PixR for displaying red (a first color: R), a pixelPixG for displaying green (a second color: G), and a pixel PixB fordisplaying blue (a third color: B), for example. In the display region111, switching elements TrD1, TrD2, and TrD3 of the pixels PixR, PixG,and PixB, respectively, the signal lines SL, the scan lines GL, and thelike are formed. The signal lines S1, S2, and S3 are wires to supplypixel signals to pixel electrodes PE1, PE2, and PE3 (refer to FIG. 6).The scan lines G1, G2, and G3 are wires to supply gate signals drivingthe switching elements TrD1, TrD2, and TrD3.

The pixels PixR, PixG, and PixB include the switching elements TrD1,TrD2, and TrD3, respectively, and each include a capacitance of a liquidcrystal layer LC. The switching elements TrD1, TrD2, and TrD3 includethin film transistors and, in this example, include n-channel metaloxide semiconductor (MOS) TFTs. A sixth insulating film 16 (refer toFIG. 6) is provided between the pixel electrodes PE1, PE2, and PE3described below and a common electrode COM, which form a holdingcapacitance Cs illustrated in FIG. 4.

In color filters CFR, CFG, and CFB illustrated in FIG. 4, color regionscolored in three colors of red (the first color: R), green (the secondcolor: G), and blue (the third color: B) are periodically arranged, forexample. The R, G, and B three-color color regions are associated withthe pixels PixR, PixG, and PixB illustrated in FIG. 4 described above asone group. The pixels PixR, PixG, and PixB corresponding to thethree-color color regions are defined as a set of pixels Pix. The colorfilters may include four-or-more-color color regions.

FIG. 5 is a schematic diagram of an example of the display panelaccording to the first embodiment. FIG. 6 is a sectional viewschematically illustrating a section of the display panel according tothe first embodiment.

As illustrated in FIG. 5, the display panel 110 has substrate end sides110 e 1, 110 e 2, 110 e 3, and 110 e 4. The region between the substrateend sides 110 e 1, 110 e 2, 110 e 3, and 110 e 4 and the display region111 of the display panel is called a peripheral region.

The scan line drive circuit 114 is placed in the peripheral regionbetween the substrate end side 110 e 1 and the display region 111 of thedisplay panel 110. The signal line connection circuit 113 is placed inthe peripheral region between the substrate end side 110 e 4 and thedisplay region 111 of the display panel 110. The driver IC 115 is placedin the peripheral region between the substrate end side 110 e 4 and thedisplay region 111 of the display panel 110. In the present embodiment,the substrate end sides 110 e 3 and 110 e 4 of the display panel 110 areparallel to the X direction. The substrate end sides 110 e 1 and 110 e 2of the display panel 110 are parallel to the Y direction.

In the example illustrated in FIG. 5, the signal lines SL extendparallel to the Y direction, whereas the scan lines GL extend parallelto the X direction. As illustrated in FIG. 5, in the present disclosure,the direction in which the scan lines GL extend is orthogonal to thedirection in which the signal lines SL extend, and thus the pixels PixR,PixG, and PixB are each a rectangular, for example. Although the exampleillustrated in FIG. 5 exemplifies a case in which the pixels PixR, PixG,and PixB are each a rectangular, they are not limited to a rectangular.The pixels PixR, PixG, and PixB may each be a parallelogram, forexample. The pixels PixR, PixG, and PixB may also be referred to as apixel PixS.

The following describes a sectional structure of the display panel 110with reference to FIG. 6. In FIG. 6, an array substrate SUB1 has a firstinsulating substrate 10 having translucency such as a glass substrate ora resin substrate as a base. The array substrate SUB1 includes a firstinsulting film 11, a second insulating film 12, a third insulating film13, a fourth insulting film 14, a fifth insulating film 15, the sixthinsulating film 16, the signal lines S1 to S3, the pixel electrodes PE1to PE3, the common electrode COM, a first orientation film AL1, and thelike on a side facing a counter substrate SUB2 of the first insulatingsubstrate 10. In the following description, the direction from the arraysubstrate SUB1 toward the counter substrate SUB2 is referred to as anupper direction or simply as upper.

The first insulting film 11 is positioned on the first insulatingsubstrate 10. The second insulating film 12 is positioned on the firstinsulting film 11. The third insulating film 13 is positioned on thesecond insulating film 12. The signal lines S1 to S3 are positioned onthe third insulating film 13. The fourth insulting film 14 is positionedon the third insulating film 13 to cover the signal lines S1 to S3.

If necessary, wiring may be placed on the fourth insulting film 14. Thiswiring will be covered with the fifth insulating film 15. The presentembodiment omits the wiring. The first insulting film 11, the secondinsulating film 12, the third insulating film 13, and the sixthinsulating film 16 are formed of an inorganic material havingtranslucency such as a silicon oxide or a silicon nitride, for example.The fourth insulting film 14 and the fifth insulating film 15 are formedof a resin material having translucency and have larger thicknesses thanthose of the other insulating films formed of the inorganic material.However, the fifth insulating film 15 may be formed of the inorganicmaterial.

The common electrode COM is positioned on the fifth insulating film 15.The common electrode COM is covered with the sixth insulating film 16.The sixth insulating film 16 is formed of an inorganic material havingtranslucency such as a silicon oxide or a silicon nitride, for example.

The pixel electrodes PE1 to PE3 are positioned on the sixth insulatingfilm 16 and face the common electrode COM via the sixth insulating film16. The pixel electrodes PE1 to PE3 and the common electrode COM areformed of a conductive material having translucency such as indium tinoxide (ITO) or indium zinc oxide (IZO), for example. The pixelelectrodes PE1 to PE3 are covered with the first orientation film AL1.The first orientation film AL1 also covers the sixth insulating film 16.

The counter substrate SUB2 has a second insulating substrate 20 havingtranslucency such as a glass substrate or a resin substrate as a base.The counter substrate SUB2 includes a light shielding layer BM, thecolor filters CFR, CFG, and CFB, an overcoat layer OC, a secondorientation film AL2, and the like on a side of the second insulatingsubstrate 20 facing the array substrate SUB1.

As illustrated in FIG. 6, the light shielding layer BM is positioned onthe side of the second insulating substrate 20 facing the arraysubstrate SUB1. The light shielding layer BM defines the size ofrespective openings facing the pixel electrodes PE1 to PE3. The lightshielding layer BM is formed of a black resin material or a lightshielding metallic material.

The color filters CFR, CFG, and CFB are positioned on the side of thesecond insulating substrate 20 facing the array substrate SUB1, and eachend thereof overlaps with the light shielding layer BM. The color filterCFR faces the pixel electrode PE1. The color filter CFG faces the pixelelectrode PE2. The color filter CFB faces the pixel electrode PE3. As anexample, the color filters CFR, CFG, and CFB are formed of resinmaterials colored in blue, red, and green, respectively.

The overcoat layer OC covers the color filters CFR, CFG, and CFB. Theovercoat layer OC is formed of a resin material having translucency. Thesecond orientation film AL2 covers the overcoat layer OC. The firstorientation film AL1 and the second orientation film AL2 are formed of amaterial indicating horizontal orientation, for example.

As described in the foregoing, the counter substrate SUB2 includes thelight shielding layer BM, the color filters CFR, CFG, and CFB, and thelike. The light shielding layer BM is placed at regions facing wiringparts such as the scan lines G1, G2, and G3 and the signal lines S1, S2,and S3 illustrated in FIG. 4, contact parts PA1, PA2, and PA3, and theswitching elements TrD1, TrD2, and TrD3.

Although in FIG. 6 the counter substrate SUB2 includes the three-colorcolor filters CFR, CFG, and CFB, it may include four-or-more-color colorfilters including color filters of other colors different from blue,red, and green such as white, transparent, yellow, magenta, and cyan.The array substrate SUB1 may include the color filters CFR, CFG, andCFB.

Although in FIG. 6 the counter substrate SUB2 is provided with the colorfilters CF, a structure of what is called a color filter on array (COA),in which the array substrate SUB1 is provided with the color filters CF,may be employed.

The array substrate SUB1 and the counter substrate SUB2 described aboveare placed such that the first orientation film AL1 and the secondorientation film AL2 face each other. The liquid crystal layer LC isenclosed between the first orientation film AL1 and the secondorientation film AL2. The liquid crystal layer LC includes a negativeliquid crystal material, the dielectric anisotropy of which is negative,or a positive liquid crystal material, the dielectric anisotropy ofwhich is positive.

The array substrate SUB1 faces a backlight unit IL, whereas the countersubstrate SUB2 is positioned on a display face side. As the backlightunit IL, ones of various kinds of aspects can be used; a description ofits detailed structure is omitted.

A first optical element OD1 including a first polarizing plate PL1 isplaced on an outer face of the first insulating substrate 10 or a facefacing the backlight unit IL. A second optical element OD2 including asecond polarizing plate PL2 is placed on an outer face of the secondinsulating substrate 20 or a face on an observation position side. Afirst polarization axis of the first polarizing plate PL1 and a secondpolarization axis of the second polarizing plate PL2 are in a positionalrelation of crossed Nicol on an X-Y plane, for example.

The first optical element OD1 and the second optical element OD2 mayinclude other optical functional elements such as a phase plate.

When the liquid crystal layer LC is the negative liquid crystalmaterial, and no voltage is applied to the liquid crystal layer LC, forexample, liquid crystal molecules LM are initially oriented in adirection such that their long axis is along the X direction within theX-Y plane. On the other hand, when voltage is applied to the liquidcrystal layer LC, that is, at the time of on, in which electric fieldsare formed between the pixel electrodes PE1 to PE3 and the commonelectrode COM, the liquid crystal molecules LM are influenced by theelectric fields to change their orientation state. At the time of on,incident linearly polarized light, when passing through the liquidcrystal layer LC, changes its polarized state in accordance with theorientation state of the liquid crystal molecules LM.

FIG. 7 is a diagram of an example of a pixel arrangement according tothe first embodiment. FIG. 8 is a schematic sectional view of thedisplay panel for illustrating influence by mutual electric lines offorce between pixels adjacent to each other. In FIG. 7, a distancebetween the pixels PixS (the pixels PixR, PixG, and PixB) in the Ydirection is defined as Phi, whereas the distance in the X direction isdefined as Pw1. FIG. 8 illustrates only the components necessary for thedescription in the present disclosure, with the other components omittedor simplified.

As illustrated in FIG. 7, in the display panel 110 according to thepresent embodiment, the color filters CF (CFR, CFG, and CFB) of thepixels PixS (the pixels PixR, PixG, and PixB) are sectioned by the lightshielding layer BM. The pixels PixS (the pixels PixR, PixG, and PixB)cause light emitted from the backlight unit IL to pass through openingsin which the color filters CF (CFR, CFG, and CFB) are provided to emitthe colors (blue, red, and green).

When a pixel voltage is applied to the pixel electrodes PE1, PE2, andPE3 to cause a potential difference between the pixel electrodes PE1,PE2, and PE3 and the common electrode COM, the pixels PixS causeelectric fields having electric lines of force emerging from the surfaceof the pixel electrodes PE1, PE2, and PE3 to reach the surface of thecommon electrode COM as indicated by the broken lines in FIG. 8.

As the pixel density of the display region 111 becomes higher, influenceby the mutual electric lines of force becomes larger between the pixelsPixS illustrated in FIG. 8. Thus, there is a possibility that the mutualelectric lines of force exert influence on each other between the pixelsPixS to cause color shift and a reduction in the accuracy of displayedcolors.

Specifically, for example, in a case in which the pixel density of thedisplay region 111 is 538 ppi (the distance Phi between the pixels PixSin the Y direction is 47.25 μm, whereas the distance Pw1 between thepixels PixS in the X direction is 15.75 μm) and a case in which thepixel density of the display region 111 is 806 ppi (the distance Phibetween the pixels PixS in the Y direction is 31.5 μm, whereas thedistance Pw1 between the pixels PixS in the X direction is 10.5 μm), thecolor shift caused by the fact that the electric lines of force betweenthe pixels PixS exert influence on each other occurs more conspicuouslyin the case in which the pixel density of the display region 111 is 806ppi.

FIG. 9 is a diagram of display relative intensity in the case of whitedisplay and monochromatic display of a pixel of each color. In FIG. 9,the vertical axis indicates a value with the maximum brightness of thepixels PixS normalized as 1, whereas the horizontal axis indicates agradation value of pixel signals supplied to the pixels PixS. FIG. 9exemplifies a case in which the pixel signals supplied to the pixelsPixS are each represented by an 8-bit value (a value with “0” as theminimum value and “255” as the maximum value).

As illustrated in FIG. 9, the gradation value giving similar displayrelative intensity is different between the white display and themonochromatic display of the pixels PixS of each color. In a range inwhich the display relative intensity is low, that is, when relativelydark display is performed, the shift of the gradation value givingsimilar display relative intensity between the white display and themonochromatic display of the pixels PixS of each color is large, forexample. Specifically, as illustrated in FIG. 9, the shift of thegradation value when the monochromatic display of the pixels PixS ofeach color with respect to the gradation value when the white display isperformed is larger when the display relative intensity is “0.2” thanwhen the display relative intensity is “0.6”. The magnitude of the shiftof the gradation value between the white display and the monochromaticdisplay giving similar display relative intensity varies by the degreeof influence of the electric lines of force between the pixels PixS suchas the pixel density of the display region 111, the width of the pixelsPixS in the X direction, the width of the pixels PixS in the Ydirection, the distance Pw1 between the pixels PixS in the X direction,and the distance Phi between the pixels PixS in the Y direction.

In the present disclosure, the gradation value varying by the degree ofinfluence of the electric lines of force between the pixels PixS iscorrected. Correction of the gradation value is preferably performedsuch that the pixels PixR, PixG, and PixB have the same relativeintensity with respect to respective gradations given to them even withany combination of the respective gradations of the pixels PixR, PixG,and PixB. In the present disclosure, as an example, based on the displayof white (that is, the intensity of the pixel PixR=the intensity of thepixel PixG=the intensity of the pixel PixB), for general display inwhich any one or more of the intensities of the pixels PixR, PixG, andPixB do not match, shift from the relative intensity of the pixels PixR,PixG, and PixB in the white display is corrected.

The following first describes the necessity of pixel gradationcorrection in the first example of the pixel configuration illustratedin FIG. 7. In FIG. 7, a pixel PixS_(m,n) present on the mth row and thenth column is a pixel for which the pixel gradation will be corrected.In the first example of the pixel configuration illustrated in FIG. 7,the width in the X direction, the width in the Y direction, the distancePw1 in the X direction, and the distance Phi in the Y direction of thepixels PixS of the respective colors (the pixels PixR, PixG, and PixB)are each the same value.

In the first example of the pixel configuration illustrated in FIG. 7,the distance Phi between the pixels PixS (the pixels PixR, PixG, andPixB) in the Y direction is larger than the distance Pw1 between thepixels PixS (the pixels PixR, PixG, and PixB) in the X direction. Insuch a pixel arrangement, influence by the electric lines of force of apixel PixS_(m,n−1) and a pixel PixS_(m,n+1), which are adjacent to thepixel PixS_(m,n) for which the pixel gradation will be corrected in theY direction, is smaller than influence by the electric lines of force ofa pixel PixS_(m−1,n) and a pixel PixS_(m+1,n), which are adjacent to thepixel PixS_(m,n) in the X direction.

Specifically, as taken as an example in which the color shift caused bythe fact that the electric lines of force between the pixels PixS exertinfluence on each other conspicuously occurs in the above, when thepixel density of the display region 111 is 806 ppi, the influence by theelectric lines of force of the pixel PixS_(m−1,n) and the pixelPixS_(m+1,n), which are adjacent to the pixel PixS_(m,n) for which thepixel gradation will be corrected with 10.5 μm (=Pw1) in the Xdirection, is conspicuous, whereas the influence by the electric linesof force of the pixel PixS_(m,n−1) and the pixel PixS_(m,n+1), which areadjacent to the pixel PixS_(m,n) for which the pixel gradation will becorrected with 31.5 μm (=Phi) in the Y direction, is extremely small.That is to say, in the first example of the pixel configurationillustrated in FIG. 7, the influence by the electric lines of force ofthe pixel PixS_(m,n−1) and the pixel PixS_(m,n+1), which are adjacent tothe pixel PixS_(m,n) for which the pixel gradation will be corrected inthe Y direction, is not necessarily required to be considered.

FIG. 10 is a diagram of a second example of the pixel arrangementaccording to the first embodiment. In the second example of the pixelarrangement illustrated in FIG. 10, the difference between the distancePhi between the pixels PixS (the pixels PixR, PixG, and PixB) in the Ydirection and the distance Pw1 between the pixels PixS (the pixels PixR,PixG, and PixB) in the X direction is smaller than that of the firstexample of the pixel configuration illustrated in FIG. 7. In such apixel arrangement, in addition to the influence by the electric lines offorce of the pixel PixS_(m−1,n) and the pixel PixS_(m+1,n), which areadjacent to the pixel PixS_(m,n) for which the pixel gradation will becorrected in the X direction, the influence by the electric lines offorce of the pixel PixS_(m,n−1) and the pixel PixS_(m,n+1), which areadjacent to the pixel PixS_(m,n) in the Y direction, is required to beconsidered. Specifically, the pixel density in the second example of thepixel arrangement illustrated in FIG. 10 assumes 2,000 ppi or more, forexample. In such a high-definition panel, pixel gradation correctionconsidering the influence by the electric lines of force of the pixelsadjacent to the pixel PixS_(m,n) for which the pixel gradation will becorrected in the X direction and the Y direction is preferablyperformed.

FIG. 11 is a diagram of a third example of the pixel arrangementaccording to the first embodiment. In the third example of the pixelconfiguration illustrated in FIG. 11, the width of a specific pixel PixS(the pixel PixG, for example) in the X direction is smaller than thoseof the other pixels PixS (the pixels PixR and PixB, for example). Insuch a pixel arrangement, the pixels PixS having a larger width in the Xdirection (the pixels PixR and PixB, for example) may be excluded fromthe pixel for which the pixel gradation will be corrected.

FIG. 12 is a block diagram of a pixel gradation correction circuitaccording to the first embodiment. As illustrated in FIG. 12, in thepresent embodiment, the display device 100 is provided with a pixelgradation correction circuit 116. The pixel gradation correction circuit116 is provided in the driver IC 115 illustrated in FIG. 3, for example.In the present disclosure, the pixel gradation correction circuit 116corresponds to a “pixel gradation corrector”.

Output of the pixel gradation correction circuit 116 is DA converted bya DAC 117 to be output to the display region 111. The DAC 117 isprovided in the driver IC 115 illustrated in FIG. 3, for example.

The component provided with the pixel gradation correction circuit 116and the DAC 117 is not limited to the driver IC 115; a componentdifferent from the driver IC 115 may be provided with the pixelgradation correction circuit 116 and the DAC 117 or the pixel gradationcorrection circuit 116 and the DAC 117 may be included as independentcomponents, for example. Image correction processing such as gammacorrection and white balance correction is preferably performed beforethe pixel gradation correction circuit 116.

The pixel gradation correction circuit 116 performs pixel gradationcorrection processing for each of the pixels PixS using Expression (1)below and Expression (2) below.

Vo _(m,n) =Vi _(m,n) −f(Vi _(m,n))×{S _(L)(Vi _(m−1,n) −Vi _(m,n))+S_(R)(Vi _(m+1,n) −Vi _(m,n))+S _(U)(Vi _(m,n−1) −Vi _(m,n))+S _(D)(Vi_(m,n+1) −Vi _(m,n))}  (1)

f(Vi _(m,n))=f _(q)(x)=A _(q) x ³ +C _(q) x ² +D _(q) x+E _(q)  (2)

In Expression (1), Vi_(m,n) indicates a pixel gradation input value (aninput gradation value) to the pixel gradation correction circuit 116 forthe pixel PixS_(m,n) for which the pixel gradation will be corrected.f(Vi_(m,n)) is a function indicating susceptibility with which the pixelPixS_(m,n) for which the pixel gradation will be corrected is influencedby adjacent pixels, that is, sensitivity with which the pixel PixS_(m,n)for which the pixel gradation will be corrected is influenced by theadjacent pixels. Vo_(m,n) indicates an output value (an output gradationvalue) of the pixel gradation correction circuit 116 having correctedthe input gradation value Vi_(m,n) for the pixel PixS_(m,n) for whichthe pixel gradation will be corrected, that is, a corrected gradationvalue as a gradation value to be output to the pixel PixS_(m,n) forwhich the pixel gradation will be corrected.

That is to say, a correction amount for the pixel PixS_(m,n) for whichthe pixel gradation will be corrected can be represented by the productof the following two terms. The first is a “value indicating sensitivityinfluenced by the adjacent pixels (the term f(Vi_(m,n)) indicated inExpression (1)”, which changes the value in accordance with the inputgradation value Vi_(m,n) that the pixel PixS_(m,n) for which the pixelgradation will be corrected should originally display. The second is aproduct of the difference between the input gradation value Vi_(m,n)that the pixel PixS_(m,n) for which the pixel gradation will becorrected should originally display and an input gradation value that apixel adjacent to the pixel should originally display and a certaincoefficient, that is, a “value indicating the strength of influence thatthe adjacent pixels exert on the pixel PixS_(m,n) for which the pixelgradation will be corrected (the term{S_(L)(Vi_(m−1,n)−Vi_(m,n))+S_(R)(Vn_(m+1,n)−Vi_(m,n))+S_(U)(Vi_(m,n−1)−Vi_(m,n))+S_(D)(Vi_(m,n+1)−Vi_(m,n))}indicated in Expression (1))”. The product of the “value indicatingsensitivity influenced by the adjacent pixels” and the “value indicatingthe strength of influence that the adjacent pixels exert on the pixelPixS_(m,n) for which the pixel gradation will be corrected” issubtracted from the input gradation value Vi_(m,n) that the pixelPixS_(m,n) for which the pixel gradation will be corrected shouldoriginally display. An output gradation value Vo_(m,n) (refer toExpression (1)) having been obtained as a result of this is given to thepixel PixS_(m,n) for which the pixel gradation will be corrected. Thus,display intensity that should originally be displayed in the pixelPixS_(m,n) for which the pixel gradation will be corrected is obtained.The following describes coefficients for calculating the “valueindicating the strength of influence that the adjacent pixels exert onthe pixel PixS_(m,n) for which the pixel gradation will be corrected”(hereinafter may be referred to simply as “coefficients indicating thestrength of influence that the adjacent pixels exert”).

S_(L) is a coefficient indicating the strength of influence that thepixel PixS_(m−1,n) adjacent to the pixel PixS_(m,n) for which the pixelgradation will be corrected on the left side in the X direction exertson the pixel PixS_(m,n). S_(R) is a coefficient indicating the strengthof influence that the pixel PixS_(m+1,n) adjacent to the pixelPixS_(m,n) for which the pixel gradation will be corrected on the rightside in the X direction exerts on the pixel PixS_(m,n). S_(U) is acoefficient indicating the strength of influence that the pixelPixS_(m,n−1) adjacent to the pixel PixS_(m,n) for which the pixelgradation will be corrected on the upper side in the Y direction exertson the pixel PixS_(m,n). S_(D) is a coefficient indicating the strengthof influence that the pixel PixS_(m,n+1) adjacent to the pixelPixS_(m,n) for which the pixel gradation will be corrected on the downside in the Y direction exerts on the pixel PixS_(m,n). Thesecoefficients S_(L), S_(R), S_(U), and S_(D) are set in advance inaccordance with the pixel arrangement of the display region 111, theshape and orientation of the pixel electrodes PE of the pixels PixS (thepixels PixR, PixG, and PixB), and the like.

Vi_(m−1,n) indicates an input gradation value, that is, an input valuebefore pixel gradation correction to the pixel gradation correctioncircuit 116 for the pixel PixS_(m−1,n) adjacent to the pixel PixS_(m,n)for which the pixel gradation will be corrected on the left side in theX direction. Vi_(m+1,n) indicates an input gradation value, that is, aninput value before pixel gradation correction to the pixel gradationcorrection circuit 116 for the pixel PixS_(m+1,n) adjacent to the pixelPixS_(m,n) for which the pixel gradation will be corrected on the rightside in the X direction. Vi_(m,n−1) indicates an input gradation value,that is, an input value before pixel gradation correction to the pixelgradation correction circuit 116 for the pixel PixS_(m,n−1) adjacent tothe pixel PixS_(m,n) for which the pixel gradation will be corrected onthe upper side in the Y direction. Vi_(m,n+1) indicates an inputgradation value, that is, an input value before pixel gradationcorrection to the pixel gradation correction circuit 116 for the pixelPixS_(m,n+1) adjacent to the pixel PixS_(m,n) for which the pixelgradation will be corrected on the down side in the Y direction.

In Expression (2), f_(q)(x) is a function indicating the sensitivitywith which the pixel PixS_(m,n) for which the pixel gradation will becorrected is influenced by the adjacent pixels. The function f_(q)(x) inExpression (2) is the same as the function f(Vi_(m,n)) indicated inExpression (1). In Expression (2), x indicates an input gradation value,that is, an input value before pixel gradation correction to the pixelgradation correction circuit 116 for the pixel PixS_(m,n) for which thepixel gradation will be corrected. The input gradation value x inExpression (2) is the same as the input gradation value Vi_(m,n) inExpression (1). A_(q), C_(q), D_(q), and E_(q) indicate coefficients setin advance in accordance with the sensitivity with which the pixelPixS_(m,n) for which the pixel gradation will be corrected is influencedby the adjacent pixels.

FIG. 13 is a diagram of an example of a function indicating thesensitivity with which the pixel for which the pixel gradation will becorrected is influenced by the adjacent pixels. In FIG. 13, thehorizontal axis indicates the input value x of the pixel gradation forthe pixel PixS_(m,n) for which the pixel gradation will be corrected,whereas the vertical axis indicates the value of the function f_(q)(x)indicating the sensitivity with which the pixel PixS_(m,n) for which thepixel gradation will be corrected is influenced by the adjacent pixels.

As illustrated in FIG. 13, the function f_(q)(x) indicating thesensitivity with which the pixel PixS_(m,n) for which the pixelgradation will be corrected is influenced by the adjacent pixels(hereinafter also referred to simply as the “function f_(q)(x)”) is avalue varying by the magnitude of the input gradation value x to thepixel gradation correction circuit 116 (hereinafter also referred tosimply as the “input gradation value x”) for the pixel PixS_(m,n) forwhich the pixel gradation will be corrected. Specifically, the functionf_(q)(x) is a value corresponding to the magnitude of the shift of thegradation value giving similar display relative intensity in the displayrelative intensity in the case of the white display and themonochromatic display of the pixels PixS of each color illustrated inFIG. 9. As illustrated in FIG. 9, in the range in which the displayrelative intensity is low, that is, in a range in which the inputgradation value x for the pixel PixS_(m,n) for which the pixel gradationwill be corrected is small, the value of the function f_(q)(x) is large,for example.

Pixel gradation correction processing for each of the pixels PixS isperformed by Expression (1) and Expression (2) using the functionf_(q)(x) determined in advance as described above, whereby the shift ofthe gradation values of the pixels PixS (the pixels PixR, PixG, andPixB) with respect to the gradation values when the white display isperformed can be corrected. More correctly, with display intensity(three stimulus values) in the case of the white display (that is, thegradation values of the pixels PixR, PixG, and PixB of an image to bedisplayed all match) as being correct, in the case of not being thewhite display (that is, there is any gradation that does not match inthe gradation values of the pixels PixR, PixG, and PixB of an image tobe displayed), the display intensities of the pixels PixR, PixG, andPixB can be compensated so as to be intensities expected as imagedisplay to be displayed. The following describes pixel gradationcorrection expressions in the pixels PixR, PixG, and PixB.

In the first example of the pixel configuration illustrated in FIG. 7,when the pixel PixS_(m,n) for which the pixel gradation will becorrected is the pixel PixR, when an input gradation value of a pixelPixR_(m,n) is Ri_(m,n)(=x), a function indicating sensitivity with whichthe pixel PixR_(m,n) is influenced by adjacent pixels is f(Ri_(m,n))(=f_(R)(x)), an input gradation value for a pixel PixB_(m−1,n), which isadjacent to the pixel PixR_(m,n) on the left side in the X direction, isBi_(m−1,n), an input gradation value for a pixel PixG_(m+1,n), which isadjacent to the pixel PixR_(m,n) on the right side in the X direction,is Gi_(m+1,n), an input gradation value for a pixel PixR_(m,n−1), whichis adjacent to the pixel PixR_(m,n) on the upper side in the Ydirection, is Ri_(m,n−1), an input gradation value for a pixelPixR_(m,n+1), which is adjacent to the pixel PixR_(m,n) on the down sidein the Y direction, is Ri_(m,n+1), a coefficient indicating the strengthof influence that the pixel PixB_(m−1,n), which is adjacent to the pixelPixR_(m,n) on the left side in the X direction, exerts is SR_(L), acoefficient indicating the strength of influence that the pixelPixG_(m+1,n), which is adjacent to the pixel PixR_(m,n) on the rightside in the X direction, exerts is SR_(R), a coefficient indicating thestrength of influence that the pixel PixR_(m,n−1), which is adjacent tothe pixel PixR_(m,n) on the upper side in the Y direction, exerts isSR_(U), a coefficient indicating the strength of influence that thepixel PixR_(m,n+1), which is adjacent to the pixel PixR_(m,n) on thedown side in the Y direction, exerts is SRD, and coefficients set inaccordance with the sensitivity with which the pixel PixR_(m,n) isinfluenced by the adjacent pixels are A_(R), C_(R), D_(R), and E_(R), acorrected gradation value for the pixel PixR_(m,n), that is, an outputgradation value Ro_(m,n) as an output value of the pixel gradationcorrection circuit 116 is indicated by Expression (3) below andExpression (4) below.

Ro _(m,n) =Ri _(m,n) −f(Ri _(m,n))×{SR _(L)(Bi _(m−1,n) −Ri _(m,n))+SR_(R)(Gi _(m+1,n) −Ri _(m,n))+SR _(U)(Ri _(m,n−1) −Ri _(m,n))+SR _(D)(Ri_(m,n+1) −Ri _(m,n))}   (3)

f(Ri _(m,n))=f _(R)(x)=A _(R) x ³ +C _(R) x ² +D _(R) x+E _(R)  (4)

In the first example of the pixel configuration illustrated in FIG. 7,when the pixel PixS_(m,n) for which the pixel gradation will becorrected is the pixel PixG, when an input gradation value of a pixelPixG_(m,n) is Gi_(m,n)(=x), a function indicating sensitivity with whichthe pixel PixG_(m,n) is influenced by adjacent pixels is f(Gi_(m,n))(=f_(G)(x)), an input gradation value for a pixel PixB_(m−1,n), which isadjacent to the pixel PixG_(m,n) on the left side in the X direction, isBi_(m−1,n), an input gradation value for a pixel PixR_(m+1,n), which isadjacent to the pixel PixR_(m,n) on the right side in the X direction,is Ri_(m+1,n), an input gradation value for a pixel PixG_(m,n−1), whichis adjacent to the pixel PixG_(m,n) on the upper side in the Ydirection, is Gi_(m,n−1), an input gradation value for a pixelPixG_(m,n+1), which is adjacent to the pixel PixG_(m,n) on the down sidein the Y direction, is Gi_(m,n+1), a coefficient indicating the strengthof influence that the pixel PixB_(m−1,n), which is adjacent to the pixelPixG_(m,n) on the left side in the X direction, exerts is SG_(L), acoefficient indicating the strength of influence that the pixelPixR_(m+1,n), which is adjacent to the pixel PixR_(m,n) on the rightside in the X direction, exerts is SG_(R), a coefficient indicating thestrength of influence that the pixel PixG_(m,n−1), which is adjacent tothe pixel PixG_(m,n) on the upper side in the Y direction, exerts isSG_(U), a coefficient indicating the strength of influence that thepixel PixG_(m,n+1), which is adjacent to the pixel PixG_(m,n) on thedown side in the Y direction, exerts is SG_(D), and coefficients set inaccordance with the sensitivity with which the pixel PixG_(m,n) isinfluenced by the adjacent pixels are A_(G), C_(G), D_(G), and E_(G), acorrected gradation value for the pixel PixG_(m,n), that is, an outputgradation value Go_(m,n) as an output value of the pixel gradationcorrection circuit 116 is indicated by Expression (5) below andExpression (6) below.

Go _(m,n) =Gi _(m,n) −f(Gi _(m,n))×{SG _(L)(Ri _(m−1,n) −Gi _(m,n))+SG_(R)(Bi _(m+1,n) −Gi _(m,n))+SG _(U)(Gi _(m,n−1) −Gi _(m,n))+SG _(D)(Gi_(m,n+1) −Gi _(m,n))}   (5)

f(Gi _(m,n))=f _(G)(x)=A _(G) x ³ +C _(G) x ² +D _(G) x+E _(G)  (6)

In the first example of the pixel configuration illustrated in FIG. 7,when the pixel PixS_(m,n) for which the pixel gradation will becorrected is the pixel PixB, when an input gradation value of a pixelPixB_(m,n) is Bi_(m,n)(=x), a function indicating sensitivity with whichthe pixel PixB_(m,n) is influenced by adjacent pixels is f(Bi_(m,n))(=f_(B)((x)), an input gradation value for a pixel PixG_(m−1,n), whichis adjacent to the pixel PixB_(m,n) on the left side in the X direction,is Gi_(m−1,n), an input gradation value for a pixel PixR_(m+1,n), whichis adjacent to the pixel PixB_(m,n) on the right side in the Xdirection, is Ri_(m+1,n), an input gradation value for a pixelPixB_(m,n−1), which is adjacent to the pixel PixB_(m,n) on the upperside in the Y direction, is Bi_(m,n−1), an input gradation value for apixel PixB_(m,n+1), which is adjacent to the pixel PixB_(m,n) on thedown side in the Y direction, is Bi_(m,n+1), a coefficient indicatingthe strength of influence that the pixel PixG_(m−1,n), which is adjacentto the pixel PixB_(m,n) on the left side in the X direction, exerts isSB_(L), a coefficient indicating the strength of influence that thepixel PixR_(m+1,n), which is adjacent to the pixel PixB_(m,n) on theright side in the X direction, exerts is SB_(R), a coefficientindicating the strength of influence that the pixel PixB_(m,n−1), whichis adjacent to the pixel PixB_(m,n) on the upper side in the Ydirection, exerts is SB_(U), a coefficient indicating the strength ofinfluence that the pixel PixB_(m,n+1), which is adjacent to the pixelPixB_(m,n) on the down side in the Y direction, exerts is SBD, andcoefficients set in accordance with the sensitivity with which the pixelPixB_(m,n) is influenced by the adjacent pixels are A_(B), C_(B), D_(B),and E_(B), a corrected gradation value for the pixel PixB_(m,n), thatis, an output gradation value Bo_(m,n) as an output value of the pixelgradation correction circuit 116 is indicated by Expression (7) belowand Expression (8) below.

Bo _(m,n) =Bi _(m,n) −f(Bi _(m,n))×{SB _(L)(Gi _(m−1,n) −Bi _(m,n))+SB_(R)(Ri _(m+1,n) −Bi _(m,n))+SB _(U)(Bi _(m,n−1) −Bi _(m,n))+SB _(D)(Bi_(m,n+1) −Bi _(m,n))}   (7)

f(Bi _(m,n))=f _(B)(x)=A _(B) x ³ +C _(B) x ² +D _(B) x+E _(B)  (8)

As described in the first example of the pixel configuration illustratedin FIG. 7, when there is no need to consider the influence by theelectric lines of force of the pixel PixS_(m,n−1) and the pixelPixS_(m,n+1), which are adjacent to the pixel PixS_(m,n) for which thepixel gradation will be corrected in the Y direction, Expression (1),Expression (3), Expression (5), and Expression (7) are indicated byExpression (10) below, Expression (11) below, Expression (12) below, andExpression (13) below, respectively.

Vo _(m,n) =Vi _(m,n) −f(Vi _(m,n))×{S _(L)(Vi _(m−1,n) −Vi _(m,n))+S_(R)(Vi _(m+1,n) −Vi _(m,n))}   (10)

Ro _(m,n) =Ri _(m,n) −f(Ri _(m,n))×{SR _(L)(Bi _(m−1,n) −Ri _(m,n))+SR_(R)(Gi _(m+1,n) −Ri _(m,n))}   (11)

Go _(m,n) =Gi _(m,n) −f(Gi _(m,n))×{SG _(L)(Ri _(m−1,n) −Gi _(m,n))+SG_(R)(Bi _(m+1,n) −Gi _(m,n))}   (12)

Bo _(m,n) =Bi _(m,n) −f(Bi _(m,n))×{SB _(L)(Gi _(m−1,n) −Bi _(m,n))+SB_(R)(Ri _(m+1,n) −Bi _(m,n))}   (13)

As described in the third example of the pixel configuration illustratedin FIG. 11, when the pixels PixS having a larger width in the Xdirection (the pixels PixR and PixB, for example) may be excluded fromthe pixel for which the pixel gradation will be corrected, thecoefficients SR_(L) and SR_(R) indicating the strength of influence thatthe adjacent pixels of the pixel PixR_(m,n) for which the pixelgradation will be corrected exert and the coefficients SB_(L) and SB_(R)indicating the strength of influence that the adjacent pixels of thepixel PixB_(m,n) for which the pixel gradation will be corrected exertare all made “0”, whereby Expression (3) and Expression (7) areindicated by Expression (14) below and Expression (15) below,respectively.

Ro _(m,n) =Ri _(m,n)  (14)

Bo _(m,n) =Bi _(m,n)  (15)

In the second example of the pixel configuration illustrated in FIG. 10,when the pixel PixS_(m,n) for which the pixel gradation will becorrected is the pixel PixR, when an input gradation value of a pixelPixR_(m,n) is Ri_(m,n)(=x), a function indicating sensitivity with whichthe pixel PixR_(m,n) is influenced by adjacent pixels is f(Ri_(m,n))(=f_(R)(x)), an input gradation value for a pixel PixB_(m,n), which isadjacent to the pixel PixR_(m,n) on the left side in the X direction, isBi_(m−1,n), an input gradation value for a pixel PixG_(m+1,n), which isadjacent to the pixel PixR_(m,n) on the right side in the X direction,is Gi_(m+1,n), an input gradation value for a pixel PixG_(m,n−1), whichis adjacent to the pixel PixR_(m,n) on the upper side in the Ydirection, is Gi_(m,n−1), an input gradation value for a pixelPixB_(m,n+1), which is adjacent to the pixel PixR_(m,n) on the down sidein the Y direction, is Bi_(m,n+1), a coefficient indicating the strengthof influence that the pixel PixB_(m−1,n), which is adjacent to the pixelPixR_(m,n) on the left side in the X direction, exerts is SR_(L), acoefficient indicating the strength of influence that the pixelPixG_(m+1,n), which is adjacent to the pixel PixR_(m,n) on the rightside in the X direction, exerts is SR_(R), a coefficient indicating thestrength of influence that the pixel PixG_(m,n−1), which is adjacent tothe pixel PixR_(m,n) on the upper side in the Y direction, exerts isSR_(U), a coefficient indicating the strength of influence that thepixel PixB_(m,n+1), which is adjacent to the pixel PixR_(m,n) on thedown side in the Y direction, exerts is SR_(D), and coefficients set inaccordance with the sensitivity with which the pixel PixR_(m,n) isinfluenced by the adjacent pixels are A_(R), C_(R), D_(R), and E_(R), acorrected gradation value for the pixel PixR_(m,n), that is, an outputgradation value Ro_(m,n) as an output value of the pixel gradationcorrection circuit 116 is indicated by Expression (16) below andExpression (17) below.

Ro _(m,n) =Ri _(m,n) −f(Ri _(m,n))×{SR _(L)(Bi _(m−1,n) −Ri _(m,n))+SR_(R)(Gi _(m+1,n) −Ri _(m,n))+SR _(U)(Gi _(m,n−1) −Ri _(m,n))+SR _(D)(Bi_(m,n+1) −Ri _(m,n))}   (16)

f(Ri _(m,n))=f _(R)(x)=A _(R) x ³ +C _(R) x ² +D _(R) x+E _(R)  (17)

In the second example of the pixel configuration illustrated in FIG. 10,when the pixel PixS_(m,n) for which the pixel gradation will becorrected is the pixel PixG, when an input gradation value of a pixelPixG_(m,n) is Gi_(m,n)(=x), a function indicating sensitivity with whichthe pixel PixG_(m,n) is influenced by adjacent pixels is f(Gi_(m,n))(=f_(G)(x)), an input gradation value for a pixel PixB_(m−1,n), which isadjacent to the pixel PixG_(m,n) on the left side in the X direction, isBi_(m−1,n), an input gradation value for a pixel PixR_(m+1,n), which isadjacent to the pixel PixR_(m,n) on the right side in the X direction,is Ri_(m+1,n), an input gradation value for a pixel PixB_(m,n−1), whichis adjacent to the pixel PixG_(m,n) on the upper side in the Ydirection, is Bi_(m,n−1), an input gradation value for a pixelPixR_(m,n+1), which is adjacent to the pixel PixG_(m,n) on the down sidein the Y direction, is Ri_(m,n+1), a coefficient indicating the strengthof influence that the pixel PixB_(m−1,n), which is adjacent to the pixelPixG_(m,n) on the left side in the X direction, exerts is SG_(L), acoefficient indicating the strength of influence that the pixelPixR_(m+1,n), which is adjacent to the pixel PixR_(m,n) on the rightside in the X direction, exerts is SG_(R), a coefficient indicating thestrength of influence that the pixel PixB_(m,n−1), which is adjacent tothe pixel PixG_(m,n) on the upper side in the Y direction, exerts isSG_(U), a coefficient indicating the strength of influence that thepixel PixR_(m,n+1), which is adjacent to the pixel PixG_(m,n) on thedown side in the Y direction, exerts is SG_(D), and coefficients set inaccordance with the sensitivity with which the pixel PixG_(m,n) isinfluenced by the adjacent pixels are A_(G), C_(G), D_(G), and E_(G), acorrected gradation value for the pixel PixG_(m,n), that is, an outputgradation value Go_(m,n) as an output value of the pixel gradationcorrection circuit 116 is indicated by Expression (18) below andExpression (19) below.

Go _(m,n) =Gi _(m,n) −f(Gi _(m,n))×{SG _(L)(Ri _(m−1,n) −Gi _(m,n))+SG_(R)(Bi _(m+1,n) −Gi _(m,n))+SG _(U)(Bi _(m,n−1) −Gi _(m,n))+SG _(D)(Ri_(m,n+1) −Gi _(m,n))}   (18)

f(Gi _(m,n))=f _(G)(x)=A _(G) x ³ +C _(G) x ² +D _(G) x+E _(G)  (19)

In the second example of the pixel configuration illustrated in FIG. 10,when the pixel PixS_(m,n) for which the pixel gradation will becorrected is the pixel PixB, when an input gradation value of a pixelPixB_(m,n) is Bi_(m,n)(=x), a function indicating sensitivity with whichthe pixel PixB_(m,n) is influenced by adjacent pixels is f(Bi_(m,n))(=f_(B)((x)), an input gradation value for a pixel PixG_(m−1,n), whichis adjacent to the pixel PixB_(m,n) on the left side in the X direction,is Gi_(m−1,n), an input gradation value for a pixel PixR_(m+1,n), whichis adjacent to the pixel PixB_(m,n) on the right side in the Xdirection, is Ri_(m+1,n), an input gradation value for a pixelPixR_(m,n−1), which is adjacent to the pixel PixB_(m,n) on the upperside in the Y direction, is Ri_(m,n−1), an input gradation value for apixel PixG_(m,n+1), which is adjacent to the pixel PixB_(m,n) on thedown side in the Y direction, is Gi_(m,n+1), a coefficient indicatingthe strength of influence that the pixel PixG_(m−1,n), which is adjacentto the pixel PixB_(m,n) on the left side in the X direction, exerts isSB_(L), a coefficient indicating the strength of influence that thepixel PixR_(m+1,n), which is adjacent to the pixel PixB_(m,n) on theright side in the X direction, exerts is SB_(R), a coefficientindicating the strength of influence that the pixel PixR_(m,n−1), whichis adjacent to the pixel PixB_(m,n) on the upper side in the Ydirection, exerts is SB_(U), a coefficient indicating the strength ofinfluence that the pixel PixG_(m,n+1), which is adjacent to the pixelPixB_(m,n) on the down side in the Y direction, exerts is SB_(D), andcoefficients set in accordance with the sensitivity with which the pixelPixB_(m,n) is influenced by the adjacent pixels are A_(B), C_(B), D_(B),and E_(B), a corrected gradation value for the pixel PixB_(m,n), thatis, an output gradation value Bo_(m,n) as an output value of the pixelgradation correction circuit 116 is indicated by Expression (20) belowand Expression (21) below.

Bo _(m,n) =Bi _(m,n) −f(Bi _(m,n))×{SB _(L)(Gi _(m−1,n) −Bi _(m,n))+SB_(R)(Ri _(m+1,n) −Bi _(m,n))+SB _(U)(Ri _(m,n−1) −Bi _(m,n))+SB _(D)(Gi_(m,n+1) −Bi _(m,n))}   (20)

f(Bi _(m,n))=f _(B)(x)=A _(B) x ³ +C _(B) x ² +D _(B) x+E _(B)  (21)

FIG. 14A is a diagram of an example of the shape of pixel electrodes inthe first example of the pixel arrangement illustrated in FIG. 7. FIG.14B is a diagram of an example in which the shape of the pixelelectrodes is different between an odd row and an even row in the firstexample of the pixel arrangement illustrated in FIG. 7. FIG. 14Billustrates an example in which the orientation of the pixel electrodesPE indicated by the broken lines is inverted in the X direction betweenthe odd row and the even row.

As illustrated in FIG. 14B, when the shape of the pixel electrodes PE ofthe pixels PixS (the pixels PixR, PixG, and PixB) is different betweenthe pixels PixS (the pixels PixR, PixG, and PixB) on the odd row and thepixels PixS (the pixels PixR, PixG, and PixB) on the even row, inExpression (1), the values of the coefficients S_(L), S_(R), S_(U), andS_(D) indicating the strength of influence that the pixels adjacent tothe pixel PixS_(m,n) for which the pixel gradation will be correctedexert may each be different values between when the pixel PixS_(m,n) forwhich the pixel gradation will be corrected is present on the odd rowand when the pixel PixS_(m,n) for which the pixel gradation will becorrected is on the odd row. When the coefficients when the pixelPixS_(m,n) for which the pixel gradation will be corrected is present onthe odd row are S_(L1), S_(R1), S_(U1), and S_(D1), and when thecoefficients when the pixel PixS_(m,n) for which the pixel gradationwill be corrected is present on the even row are S_(L2), S_(R2), S_(U2),and S_(D2), a gradation value Vo1_(m,n) after gradation correction ofthe pixel PixS_(m,n) when the pixel PixS_(m,n) for which the pixelgradation will be corrected is present on the odd row and a gradationvalue Vo2_(m,n) after gradation correction of the pixel PixS_(m,n) whenthe pixel PixS_(m,n) for which the pixel gradation will be corrected ispresent on the even row are indicated by Expression (22) below andExpression (23), respectively.

Vo1_(m,n) =Vi _(m,n) −f(Vi _(m,n))×{S _(L1)(Vi _(m−1,n) −Vi _(m,n))+S_(R1)(Vi _(m+1,n) −Vi _(m,n))+S _(U1)(Vi _(m,n−1) −Vi _(m,n))+S _(D1)(Vi_(m,n+1) −Vi _(m,n))}   (22)

Vo2_(m,n) =Vi _(m,n) −f(Vi _(m,n))×{S _(L2)(Vi _(m−1,n) −Vi _(m,n))+S_(R2)(Vi _(m+1,n) −Vi _(m,n))+S _(U2)(Vi _(m,n−1) −Vi _(m,n))+S _(D2)(Vi_(m,n+1) −Vi _(m,n))}   (23)

In Expression (22) and Expression (23), when the orientation of thepixel electrodes PE is inverted in the X direction between the odd rowand the even row as illustrated in FIG. 14B, for example, S_(L1) andS_(L2), S_(R1) and S_(R2), S_(U1) and S_(U2), and S_(D1) and S_(D2) areindicated by values with inverted signs for each pair.

The following describes Expression (1) and Expression (2) in ageneralized manner.

When the input gradation value of the pixel PixS_(m,n) for which thepixel gradation will be corrected (hereinafter referred to as a “firstpixel”) is V1i, the function indicating the sensitivity with which thefirst pixel is influenced by the pixel PixS_(m−1,n), the pixelPixS_(m+1,n), the pixel PixS_(m,n−1), and the pixel PixS_(m,n+1), whichare adjacent to the first pixel, (hereinafter referred to as “secondpixels”) is f(V1i), the number of the second pixels adjacent to thefirst pixel is N, the input gradation value of the second pixels is V2i,and the coefficient indicating the strength of influence that the secondpixels exert is Sp, Expression (1) can be indicated by Expression (24)below.

$\begin{matrix}{{V\; 1o} = {{V\; 1i} - {{f( {V1i} )}{\sum\limits_{p = 1}^{N}{S{p( {{V2i} - {V1i}} )}}}}}} & (24)\end{matrix}$

As to the function f(V1i) indicating the sensitivity with which thefirst pixel is influenced by the second pixels, when the input gradationvalue Vii of the first pixel is x, and the coefficients set in advancein accordance with the sensitivity with which the first pixel isinfluenced by the second pixels are A, C, D, and E, Expression (2) canbe indicated by Expression (25) below.

f(V1i)=f(x)=Ax ³ +Cx ² +Dx+E  (25)

By the pixel gradation correction processing for each of the pixels PixSdescribed in the present embodiment, the shift of the gradation valuesof the pixels PixS (the pixels PixR, PixG, and PixB) with respect to thegradation values when the white display is performed can be corrected.More correctly, with display intensity (three stimulus values) in thecase of the white display (that is, the gradation values of the pixelsPixR, PixG, and PixB of an image to be displayed all match) as beingcorrect, in the case of not being the white display (that is, there isany gradation that does not match in the gradation values of the pixelsPixR, PixG, and PixB of an image to be displayed), the displayintensities of the pixels PixR, PixG, and PixB can be compensated so asto be intensities expected as image display to be displayed.

According to the present embodiment, the display device 100 and thedisplay system 1 can inhibit a reduction in the accuracy of displayedcolors along with higher definition.

Second Embodiment

FIG. 15 is a block diagram of a pixel gradation correction circuitaccording to a second embodiment. For the components similar to or thesame as those of the first embodiment described above, a duplicatedescription is omitted.

As illustrated in FIG. 15, in the present embodiment, an imagegeneration device 200 a is provided with a pixel gradation correctioncircuit 250. The pixel gradation correction circuit 250 is provided inthe control circuit 230 illustrated in FIG. 3, for example. Thecomponent provided with the pixel gradation correction circuit 250 isnot limited to the control circuit 230; a component different from thecontrol circuit 230 may be provided with the pixel gradation correctioncircuit 250 or the pixel gradation correction circuit 250 may beincluded as an independent component, for example. In the presentdisclosure, the pixel gradation correction circuit 250 corresponds tothe “pixel gradation corrector”.

Output of the pixel gradation correction circuit 250 is DA converted bythe DAC 117 provided in a display device 100 a to be output to thedisplay region 111. The DAC 117 is provided in the driver IC 115illustrated in FIG. 3, for example.

As illustrated in FIG. 15, in the configuration in which the imagegeneration device 200 a is provided with the pixel gradation correctioncircuit 250 as well, image correction processing such as gammacorrection and white balance correction is preferably performed beforethe pixel gradation correction circuit 250 like the first embodiment.

According to the present embodiment, the display device 100 a and adisplay system 1 a can inhibit a reduction in the accuracy of displayedcolors along with higher definition.

The preferred embodiments of the present disclosure have been described;the present disclosure is not limited to such embodiments. The detailsdisclosed in the embodiments are only by way of example, and variousmodifications can be made in a range not departing from the gist of thepresent disclosure. Appropriate modifications made in the range notdeparting from the gist of the present disclosure also naturally belongto the technical scope of the present invention, for example.

What is claimed is:
 1. A display device comprising: a liquid crystaldisplay panel having a display region; pixels provided in the displayregion and arranged in a matrix (row-column configuration) in a firstdirection and a second direction different from the first direction; anda pixel gradation corrector correcting a gradation value of a firstpixel in accordance with gradation values of second pixels adjacent tothe first pixel, the pixel gradation corrector multiplying a valueindicating sensitivity with which the first pixel is influenced by thesecond pixels and a value indicating strength of influence that thesecond pixels exert on the first pixel together, and subtracting themultiplied value from an input gradation value of the first pixel tocalculate an output gradation value to the first pixel.
 2. The displaydevice according to claim 1, wherein the pixel gradation correctorcalculates an output gradation value V1o to the first pixel usingExpression (1) below when the input gradation value of the first pixelis V1i, a function indicating sensitivity with which the first pixel isinfluenced by the second pixels is f(V1i), number of the second pixelsis N, an input gradation value of the second pixels is V2i, and acoefficient indicating strength of influence that the second pixelsexert on the first pixel is Sp: $\begin{matrix}{{V\; 1o} = {{V\; 1i} - {{f( {V1i} )}{\sum\limits_{p = 1}^{N}{S{p( {{V2i} - {V1i}} )}}}}}} & (1)\end{matrix}$
 3. The display device according to claim 2, wherein thefunction f(V1i) is indicated by Expression (2) below when the inputgradation value V1i of the first pixel is x, and coefficients set inadvance in accordance with the sensitivity with which the first pixel isinfluenced by the second pixels are A, C, D, and E:f(V1i)=f(x)=Ax ³ +Cx ² +Dx+E  (2)
 4. The display device according toclaim 1, wherein the pixels include a first pixel for displaying a firstcolor, a second pixel for displaying a second color different from thefirst color, and a third pixel for displaying a third color, the thirdcolor being different from the first color and the second color.
 5. Adisplay system comprising: a display device including a liquid crystaldisplay panel having a display region, and pixels provided in thedisplay region and arranged in a matrix (row-column configuration) in afirst direction and a second direction different from the firstdirection; and an image generation device including a pixel gradationcorrector correcting a gradation value of a first pixel in accordancewith gradation values of second pixels adjacent to the first pixel, thepixel gradation corrector multiplying a value indicating sensitivitywith which the first pixel is influenced by the second pixels and avalue indicating strength of influence that the second pixels exert onthe first pixel together, and subtracting the multiplied value from aninput gradation value of the first pixel to calculate an outputgradation value to the first pixel.
 6. The display system according toclaim 5, wherein the pixel gradation corrector calculates an outputgradation value V1o to the first pixel using Expression (3) below whenthe input gradation value of the first pixel is V1i, a functionindicating sensitivity with which the first pixel is influenced by thesecond pixels is f(V1i), number of the second pixels is N, an inputgradation value of the second pixels is V2i, and a coefficientindicating strength of influence that the second pixels exert on thefirst pixel is Sp: $\begin{matrix}{{V\; 1o} = {{V\; 1i} - {{f( {V1i} )}{\sum\limits_{p = 1}^{N}{S{p( {{V2i} - {V1i}} )}}}}}} & (3)\end{matrix}$
 7. The display system according to claim 6, wherein thefunction f(V1i) is indicated by Expression (4) below when the inputgradation value V1i of the first pixel is x, and coefficients set inadvance in accordance with the sensitivity with which the first pixel isinfluenced by the second pixels are A, C, D, and E:f(V1i)=f(x)=Ax ³ +Cx ² +Dx+E  (4)
 8. The display system according toclaim 5, wherein the pixels include a first pixel for displaying a firstcolor, a second pixel for displaying a second color different from thefirst color, and a third pixel for displaying a third color, the thirdcolor being different from the first color and the second color.